The production of hydrocarbons (e.g. crude oil and gas) from subsea reservoirs is facilitated by multiple large offshore production facilities located near one or more subsea wells.
Traditionally, the hydrocarbons have been transported from the offshore production facility to onshore storage facilities and further processing, via pipelines laid on the seabed. However, as hydrocarbons are being produced from reservoirs located in deeper and deeper waters and in regions where the seabed includes rough or uneven terrain such as steep cliffs and deep canyons, the use of seabed pipelines has become increasingly complex and prohibitively expensive.
Thus, a more economical and flexible system for transporting the hydrocarbons to onshore locations involve the use of offshore storage facilities at or near the production location, in combination with shuttle tankers. The offshore storage facility may comprise subsea storage cells integrated with a so-called Gravity Base Structure (GBS) platform or connected to a loading buoy of a fixed platform, or the offshore storage facility may be integrated in a so-called Floating Production, Storage and Offloading (FPSO) vessel which is maintained in position in a manner which is known in the art (e.g. moorings and/or thrusters controlled by dynamic positioning).
The hydrocarbons are transferred from the offshore storage facility (e.g. platform) to the carrier (e.g. a shuttle tanker) via a flexible transfer conduit, commonly referred to as a marine hose. When not in use, the hose is stored on a reel on the platform. Before commencing offloading of hydrocarbons, the flexible hose is paid out from the reel and connected to the shuttle tanker. When offloading is complete, the hose is disconnected from the tanker and reeled back onto the reel, in a manner known in the art.
Hose reels are commonly driven by a slew bearing assembly, i.e. a slewing gear rim (driven by one or more slewing motors) and a bearing raceway, connected to the reel and the reel stand, respectively, or vice versa. This mechanism is well known in the art.
Frequent use, with considerable torque and radial loads, cause wear and tear on the slew bearing assembly, and from time to time the assembly fails. Repairs, e.g. replacing the slewing gear rim or the bearing raceway, are often time consuming, causing expensive downtime for the platform.